This invention relates generally to the ventilation system of an electric-drive vehicle, and more particularly, to a multiple outlet centrifugal blower configuration in an electric-drive mining vehicle.
Centrifugal blowers are designed to move quantities of air by raising the pressure of the air and discharging it at a desired volumetric flow rate through a pipe or duct. An apparatus requiring cooling, ventilation, or pressurization is often positioned at the discharge port of the pipe or duct. In order for the air to move at a continuous volumetric flow rate through the discharge port to cool, ventilate, or pressurize the apparatus, the air must be supplied with sufficient energy to overcome the downstream backpressure at the outlet. This backpressure is the sum of the pressure drop in the downstream system caused by the resistance of the air moving through the duct and the total air pressure at the discharge port. Oftentimes the downstream system has at least two separate branches through which air must be delivered to a corresponding number of components that require cooling, ventilation, or pressurization. These systems typically include blowers having two or more separate impellers wherein each impeller supplies air at a volumetric flow rate specific to the apparatus connected to its respective discharge port.
Such systems are incorporated into electric-drive off-road mining trucks and various other earth-moving devices, railroad locomotives, and marine vessels. One such mining truck is the KMS 930E provided by Komatsu Mining Systems (www.komatsumining.com). The drive system for such trucks includes a diesel-driven alternator that provides electrical power through a control group to AC drive motors connected to the wheels of the truck. A significant amount of heat is generated during the operation of the AC drive motors. This heat is removed from the drive motors by a supply of cooling air.
It is known to provide cooling air for such mining vehicles from a centrifugal blower connected directly to the drive shaft of the alternator. U.S. Pat. No. 4,448,573 describes a multiple outlet centrifugal blower for such applications. The blower casing includes two outlets that are displaced from one another so as to provide two independent flows of cooling air. One of the airflows is directed to cool the alternator and the other is directed to cool the drive motors. The arcuate extent of the respective outlet openings around the periphery of the impeller may be selected to control the pressure and volume flow rate of the respective airflows. In this type of blower, the total velocity head generated by the impeller blades at the respective arcuate position is used to drive the airflow into the respective outlet.
In addition to removing heat from the alternator and the drive motors, heat must also be removed from the electrical control group components of an electric-drive vehicle. In modern large mining vehicles, the airflow from the alternator shaft blower is dedicated to cooling the alternator. Cooling air for the drive motors and the control group is provided from two respective impellers situated on a single double-ended auxiliary blower unit. Air moved by the first impeller is ducted to the rear of the vehicle where it is used to cool the AC drive motors located inside the rear wheels of the truck. Air moved by the second impeller is ducted to the deck of the vehicle and is used to cool electrical components associated with the control group of the vehicle. The auxiliary blower unit is driven by an auxiliary AC drive motor, which is powered by an auxiliary inverter connected to the alternator. Such an independent dual-impeller ventilation system offers the benefit of providing independent cooling air flows to the alternator, control group and drive motors. However, such a configuration is mechanically complex and costly to build and to maintain.
What is needed is a ventilation system for an electric drive vehicle that eliminates the auxiliary blower unit yet still provides an independent cooling air flow for each of the alternator, control group and drive motors.
An apparatus is described herein for providing a flow of pressurized air to each of an alternator, a control group component and an electric drive motor of an electric-drive vehicle. The apparatus includes a housing having an inlet for receiving air; an impeller rotatable about an axis within the housing to accelerate the air in both a radial direction and an axial direction; a first outlet opening formed in a perimeter of the housing to receive a first radial airflow from the impeller for directing the first radial airflow to a first of the alternator, the control group component and the electric drive motor; a second outlet opening formed in the perimeter of the housing radially remote from the first outlet to receive a second radial airflow from the impeller for directing the second radial airflow to a second of the alternator, the control group component and the electric drive motor; and a third outlet opening formed in a side of the housing to receive an axial airflow from the impeller for directing the axial airflow to a third of the alternator, the control group component and the electric drive motor. The third outlet opening may be a generally ring-shaped opening formed in the side of the housing proximate a perimeter of the impeller; and the apparatus may also include an air dam blocking a portion of the ring-shaped opening at a radial location proximate the first outlet opening.
A centrifugal blower is described herein as including: a housing having an inlet for receiving air; an impeller rotatable about an axis within the housing to accelerate the air in both a radial direction and an axial direction; a first outlet opening formed in a perimeter of the housing for receiving a radial airflow from the impeller; a second outlet opening formed in a side of the housing for receiving an axial airflow from the impeller; and a pressure barrier disposed between the first outlet opening and the second outlet opening to isolate the radial airflow from the axial airflow.
An electric-drive vehicle is describe herein as including an internal combustion engine, an alternator driven by the engine, a drive motor powered by the alternator for propelling the vehicle, and a heat-generating control group component, the electric-drive vehicle further including; a blower driven by the engine for producing pressurized air for cooling the alternator, the drive motor and the control group component, the blower further including: a housing; an impeller rotatable about an axis within the housing to accelerate air in both a radial direction and an axial direction; an opening formed in a perimeter portion of the housing for receiving a radial airflow from the impeller; and an opening formed in a side portion of the housing for receiving an axial airflow from the impeller.
An enhanced ventilation system utilizes a blower having a single centrifugal impeller coupled directly to the power plant of a vehicle to provide independent flows of air to cool, ventilate, or pressurize at least two and preferably three of the vehicle components. In one embodiment, the ventilation system is installed in an electric-drive mining vehicle utilizing a diesel-powered drive engine. A single blower attached to the alternator drive shaft provides pressurized air to cool the alternator, the drive motors and/or the control group components of the vehicle. The blower design takes advantage of the separate axial and radial velocity components of the air propelled by the impeller to provide the independence of the airflows.
The term “alternator” is used herein to describes machines that produce alternating current as well as machines that produce direct current. Such DC-producing machines are sometimes referred to as generators. For simplicity, such DC-producing machines are included herein under the term alternator.
Referring to
An inlet chamber, shown generally at 16, is positioned and connected adjacent to housing 14. Inlet chamber 16 serves as the means through which the air is supplied to impeller 12 and comprises a front wall 18 and a back wall 20 positioned in a substantially parallel planar relationship and connected by at least one sidewall 22. The top portion of inlet chamber 16 is open to allow air to enter, while the bottom portion is closed. In one embodiment, the bottom portion is curved to define a continuous wall that forms each sidewall 22, thereby saving space and material in the construction of inlet chamber 16. Back wall 20 is configured to extend toward front wall 18 proximate the center portion of back wall 20. A hole in the center portion of back wall 20 is dimensioned to receive a rotating shaft 24, and apertures are located proximate the hole in the center portion of back wall 20 to accommodate outlet ducts. Front wall 18 has an opening formed in the center portion thereof to accommodate a frame head 26. Inlet chamber 16 may be either fabricated from sheet metal (e.g., steel or aluminum) or molded from a suitable material (e.g., fiberglass).
Housing 14 comprises a structure similar to inlet chamber 16 and is connected to an outer surface of back wall 20 of inlet chamber 16. Housing 14 is configured and dimensioned to closely accommodate the width of each impeller blade 13 and to allow impeller 12 to freely rotate such that the clearance between each blade 13 and the inner walls of housing 14 is minimal. A hole extending through the center portion of housing 14 corresponds with the hole in inlet chamber 16 to receive rotating shaft 24 there through.
Impeller 12 comprises a hub 32 and blades 13 extending from a center portion of hub 32. Blades 13 are tapered and flat and may be either of the paddle-type or of the curvilinear-type in which each blade 13 is curved along a longitudinal plane of its body. Hub 32 is suitably mounted on rotating shaft 24 that extends through housing 14 and inlet chamber 16 where it is rotatably supported by bearings 34 in frame head 26. Rotating shaft 24 is an extension of a rotor shaft, which may be an electric current alternator driven by a diesel engine (not shown) at a speed in the range of 1,800 to about 2,100 revolutions per minute. As shown in
The side of housing 14 opposite the side to which inlet chamber 16 is connected comprises a first outlet duct and a second outlet duct, shown generally at 36 and 36, respectively. First outlet duct 34 is joined to housing 14 proximate an edge thereof and serves as a means through which air expelled by blower 10 is ducted to system components, e.g., control group elements that pneumatically regulate the supply of pressurized air to operate valves, temperature controllers, fluid-level controllers, safely devices, and other components (not shown). In a preferred embodiment, first outlet duct 34 is positioned at the topmost portion of housing 14 when blower 10 is oriented such that impeller 12 is substantially vertical relative to a level plane of a ground surface (not shown). A throat portion 38 of first outlet duct 34 is dimensioned to have a width that is substantially equal to the width of an impeller blade 13. Throat portion 38 becomes increasingly wider near an outer edge 40 of first outlet duct 34 to enable first outlet duct 34 to be connected to ductwork (not shown) that provides a pathway for air ejected there from to be channeled to the system components that require pressurized air. As can be best seen in
In
Second outlet duct 36 is joined to housing 14 proximate an edge thereof and is positioned substantially diametrically opposite first outlet duct 34 and serves as a means through which air expelled by blower 10 is ducted away. The axial velocity component of the air drives the air into second outlet duct 36. In one embodiment, the air is ducted to the rear of a truck to ventilate and cool the AC drive motors (not shown) that drive the truck. Second outlet duct 36 extends laterally away from housing 14 to connect to ductwork (not shown), which may or may not be flexible hosing. A second access cover 46 is removably fastened to housing 14 over second outlet duct 36 in order to allow access to impeller 12 without disassembling housing 14.
Referring to
The shape of third outlet 90 may be better appreciated by viewing
In the embodiment of
The first outlet 82 is formed in the perimeter of the housing radially remote from the second outlet 86 in order to provide relatively independent fluid flow characteristics to the first radial airflow 84 and the second radial airflow 88. The fluid flow independence of the axial airflow 92 is provided by the distinct radial and axial velocity components of the air as it is accelerated by the impeller 78. In the embodiment of
While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.
This application is a continuation in-part of the Sep. 29, 2000, filing date of U.S. patent application Ser. No. 09/676,009, now U.S. Pat. No. 6,382,911 B1 dated May 7, 2002.
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Number | Date | Country | |
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20020110452 A1 | Aug 2002 | US |
Number | Date | Country | |
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Parent | 09676009 | Sep 2000 | US |
Child | 10126701 | US |